1. Field of the Invention
The invention relates to a method for restoring an image for an electronic device and a related device and, more particularly, to a method for restoring an image and a related device for restoring an image of a photographed object according to an acceleration signal generated when the electronic device moves and the distance between the electronic device and the photographed object.
2. Description of the Prior Art
With the widespread usage of digital cameras, people require more and more to image quality. For example, the resolution of the image, the saturation of the color and other parameters become necessary considerations when a consumer chooses a digital camera product. More importantly, when the consumer takes photos using a handheld digital camera, the shake of hand may blur the image, and the definition of the image decreases. Therefore, an anti-shake function is necessary in a digital camera.
The conventional anti-shake technique may be divided into an optical anti-shake technique and an electronic anti-shake technique. The optical anti-shake technique is achieved by hardware, and the common method is setting a sensing device such as an accelerometer or a gyroscope in a lens module of the camera, or it may be combined with a charge coupled device (CCD) sensor inside the camera to detect the shake degree of the lens or the camera body when the hand shakes and transfer detected data to the processor in the camera body. The processor controls the lens in the lens module or the CCD sensor to move to compensate the displacement to obtain a stable image after a computing process. Although the optical anti-shake technique may amend the blurred image precisely, the price is high, and much space is occupied. In addition, hardware may be damaged when the electronic device is fallen off. Thus, the optical anti-shake technique cannot be applied to small electronic devices such as a camera phone or a lightweight digital camera.
In addition, the electronic anti-shake technique processes and restores the blurred image by software. The electronic anti-shake technique does not need additional hardware detecting devices, and thus it is always used in small electronic products. It is common to use high international standards organization (ISO) technique to control a shutter to finish photographing before the camera moves. Since the high ISO technique is weak in light-collection, signal intensity should be improved, and thus high noise is generated. Another common method is to estimate the moving path of the blurred image namely the point spread function (PSF) according to a special algorithm such as the Lucy-Richardson algorithm and restore the image according to the PSF. However, estimating the PSF of the high resolution image by the algorithm needs much computing time, and it is not practical.